From d52c1bcc647ca41ee563bc38d8231e5f3816112c Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Tue, 5 Nov 2013 11:45:53 +0800 Subject: Btrfs: avoid heavy operations in btrfs_commit_super The 'git blame' history shows that, the old transaction commit code has to do twice to ensure roots are updated and we have to flush metadata and super block manually, however, right now all of these can be handled well inside the transaction commit code without extra efforts. And the error handling part remains same with the current code, -- 'return to caller once we get error'. This saves us a transaction commit and a flush of super block, which are both heavy operations according to ftrace output analysis. Signed-off-by: Liu Bo Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/disk-io.c | 21 +-------------------- 1 file changed, 1 insertion(+), 20 deletions(-) (limited to 'fs') diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 4c4ed0bb3da1..8072cfa8a3b1 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3517,7 +3517,6 @@ int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info) int btrfs_commit_super(struct btrfs_root *root) { struct btrfs_trans_handle *trans; - int ret; mutex_lock(&root->fs_info->cleaner_mutex); btrfs_run_delayed_iputs(root); @@ -3531,25 +3530,7 @@ int btrfs_commit_super(struct btrfs_root *root) trans = btrfs_join_transaction(root); if (IS_ERR(trans)) return PTR_ERR(trans); - ret = btrfs_commit_transaction(trans, root); - if (ret) - return ret; - /* run commit again to drop the original snapshot */ - trans = btrfs_join_transaction(root); - if (IS_ERR(trans)) - return PTR_ERR(trans); - ret = btrfs_commit_transaction(trans, root); - if (ret) - return ret; - ret = btrfs_write_and_wait_transaction(NULL, root); - if (ret) { - btrfs_error(root->fs_info, ret, - "Failed to sync btree inode to disk."); - return ret; - } - - ret = write_ctree_super(NULL, root, 0); - return ret; + return btrfs_commit_transaction(trans, root); } int close_ctree(struct btrfs_root *root) -- cgit v1.2.3